Free guide · Oct 13, 2026
Reverse engineer any app with Claude and REA
Set up REA in one command on Windows or Mac, run it with an uncensored local model, and try ten weekend projects with copy-paste prompts.
The short version
REA (Reverse Engineer Anything) is a free, open-source add-on for AI coding agents. You point your agent at an app you don't have the code for, ask how one feature works, and it looks inside the app, shows you the evidence for every finding, and then builds your own version of that feature in your project.
•What it costs: nothing. REA is MIT licensed. You pay only for the agent or model you already use, or nothing at all with a local model.
•What you need: Node.js and an AI coding agent such as Claude Code, Codex, Cursor or Gemini CLI. Windows, Mac and Linux all work.
•Setup: one command, `npx rea-agents setup`, then restart your agent. About ten minutes the first time.
What's in the full guide
- 01Part 1. What REA is and what it can do
- 02Part 2. Set up in about ten minutes
- 03Part 3. Uncensored models
- 04Part 4. Ten projects to try this weekend
- 05Part 5. The prompt library
- 06Part 6. Use it responsibly
- 07Sources